Hours: 07–23 daily

TuningBot DTC Database · v4.38.5

U300C Ignition Input Off/On/Start

Generic (OBD-II) interpretation in the TuningBot DTC database.

U · NetworkNetworkOBD2

What U300C means

U300C
Ignition Input Off/On/Start Generic · network Data confidence 78%

The control module detected a fault associated with the Ignition Input Off/On/Start circuit or function; the stored code identifies the affected component rather than a single failure mode.

Symptoms

  • Multiple warning lamps possible
  • Functions of the affected module unavailable

Possible causes

  • CAN bus wiring fault (open, short, chafed harness)
  • Faulty control module loading the bus
  • Connector or terminal corrosion
  • Power supply or ground fault of a module

Recommended checks

  • Perform a full-module scan to map which modules communicate
  • Check CAN bus resistance and voltages at the diagnostic connector
  • Inspect wiring and connectors of the affected module
  • Check module power supply and grounds
  • Disconnect suspect modules one at a time only with a documented procedure

Related and nearby codes

How to read U300C

U

Network: communication between control units.

3

Generic SAE-standard code: same meaning on every make.

00C

Specific fault index within the subsystem.

Frequently asked questions about U300C

What does U300C mean?

Ignition Input Off/On/Start. The control module detected a fault associated with the Ignition Input Off/On/Start circuit or function; the stored code identifies the affected component rather than a single failure mode.

Is U300C generic or manufacturer-specific?

U300C is a generic OBD-II code: it has the same meaning on every make and model that follows the SAE standard.

Can TuningBot remove U300C at file level?

Not guaranteed. Powertrain (P) codes can be reliably disabled in the ECU calibration, but body, chassis and network codes depend on the specific control unit and how the fault is implemented - some can be handled, some cannot. Ask for a quote and our engineers will check your file and tell you, free of charge, whether U300C is removable in your case.

Other file services

ECU tuningDyno-tested results by model and engine See the results →

← Search the full DTC database